Mullvad VM error: unable to provide network to other VMs

User Support
1

In version 4.1 I did this and mullvad’s dns was updated successfully and the web page could be accessed.
In version 4.2, this script keeps reporting an error about the QSB rules being wrong, the dns not working correctly, and the web page is inaccessible, but the internet works.

2

What are QSB rules?

3

You are talking about the chain name I guess:

It does not work for Qubes 4.2 because it uses the old iptables nat dns chain name.

Here is the corrected script with the correct chain name and a few edits:

#! /usr/bin/env bash

update_dns() {
	# mullvad_on: 0 -> off, 1 -> on
	mullvad_on=$([[ $(grep -v -c "nameserver \+10.139" /etc/resolv.conf) -gt 0 ]] && echo 1 || echo 0)

	if [[ $mullvad_on -eq 1 ]]; then

		echo "Mullvad is on"

		# get the mullvad dns ip address. First one is used if there is more than one.
		mullvad_dns_ip=$(grep "nameserver" < /etc/resolv.conf| awk '{print $2}' | head -n 1)

		# delete all the lines defined in dnat-dns
		sudo nft flush chain ip qubes dnat-dns

		# forward all dns requests to mullvad dns servers
		sudo nft add rule ip qubes dnat-dns meta l4proto { udp, tcp } ip daddr { 10.139.1.1, 10.139.1.2 } th dport 53 dnat to "$mullvad_dns_ip"

	else

		echo "Mullvad is off"

		# get qubes nameserver ip addresses
		nameserver_ips=$(grep "nameserver" < /etc/resolv.conf| awk '{print $2}')

		# delete all the lines defined in dnat-dns
		sudo nft flush chain ip qubes dnat-dns

		# add rule to forward dns requests to qubes nameservers
		for ip in $nameserver_ips; do
			sudo nft add rule ip qubes dnat-dns ip daddr "$ip" udp dport 53 dnat to "$ip"
			sudo nft add rule ip qubes dnat-dns ip daddr "$ip" tcp dport 53 dnat to "$ip"
		done

	fi
}

update_dns
# check for /etc/resolv.conf content change
inotifywait -m -q -e close_write /etc/resolv.conf | while read -r;
do
	update_dns
done
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